Modifying a leading zero estimation during an unfused multiply add operation of (A*B)+C. A plurality of terms x and y may be received, and each may be based on truncated terms s and t (e.g., in performing the unfused multiply add operation) and the shifted C term. A first leading zero estimation may be calculated based on the terms x and y. It may be determined if near total catastrophic cancellation has occurred. A carry in from a right most number of bits of the terms s and t and the most significant truncated bits of s and t may be used to generate a second leading zero estimation based on the first leading zero estimation if the near total catastrophic cancellation has occurred.